GENETICS PROBLEM!! HELP ASAP!!?

Rhesus factor (Rh) is a second autosomally inherited trait that determines a blood type in humans. The Rhesus positive trait is dominant to Rhesus negative. It sorts independently from the ABO gene. Alan has blood type A and is Rhesus positive. His father, John has blood type B and is Rhesus negative, while his mother Angela has blood type AB and is Rhesus positive. Alan marries Gillian, who has blood type O and is Rhesus negative. What is the probability of Alan and Gillian's children being blood type O and Rhesus negative?

Comments

  • Alan's genotype must be AO +-

    because he had to have gotten the O and - from his father.

    Gillian is OO --

    The chance of their child getting an O from Alan is 1/2, and the chance of the child getting a - from Alan is also 1/2. The chance of getting an O and a - from Gillian is 1 (that's all she has).

    So the chance of the child getting the O and the - from both parents is

    1/2 x 1/2 x 1 x 1 = 1/4.

  • i think it would be 1/4 chance... if he's positive and you're doing your square he would prevent the occurrence of neg/neg 3/4 of the time... thats if im remembering my genetics correctly

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